Why won't my water pump stop if there's no leak ?

[Ray Jones]

I have the same problem on my Bavaria. I have even fitted a new pump and still the problem persists. I have resorted to isolating at the panel every time I turn the tap off. No leaks, no faulty diaphragm and plenty of water in the system.
Many have said that jabsco are unreliable. Does anyone know of a suitable alternative.

[ranger58sb]

Originally Posted by motion30

Turns out the jabsco pumps are just junk

Yeah, our first one only lasted 14 years...

-Chris

[Stu Jackson]

[QUOTE=Ray Jones;2412878
Many have said that jabsco are unreliable. Does anyone know of a suitable alternative.[/QUOTE]

Shurflo or Johnson.

[thinwater]

An accumulator tank is really vital. Water is an imcompressible fluid, unlike air. Bleed off one drop, perhaps through a check valve that has a tiny leak, the pressure drops, and the pump cycles. Some boats have more problems with this than others, because the amount and type of piping provides some accumulation capacity (the tubing stretches).

Add the tank. An alternative, for boats that like to minimize weight, is you use a small centrifugal pump and turn it on only when water is being used. Then no tank is needed. This will not suit large boats or feed filters. I used one of these on a Stiletto 27. And there are always foot pumps.

https://www.amazon.com/dp/B01M5DMYC8...a-321413923120

[cal40john]

How long did you purge the lines? I've had water come out the faucet when there was still an air bubble at the pump which causes the pump to not shut off. Running the faucet longer until all the air is out has fixed my problem. (Except for when I first got the boat and the pump was old and broken.)

[Cheechako]

Turn on furthest taps from the pump, let it run a awhile, turn on closer taps, you likely have air trapped somewhere. Without an accumulator it will run with even a small tap opening... no big deal. But should shut off fine. Are your filters mounted top up?

[donradcliffe]

Before you tear anything apart, try running the pump with faucets full open for 30 seconds to make sure you have purged the air in the system.

[Ivansgarage]

It says NO accumulator.
The pressure could be blocked by foreign matter it's just a small hole.

https://jet.com/product/detail/98482...FQ90fgodbf8J8A


Jabsco PAR-Max 2.9 Automatic Water Pressure System Pump

PAR-Max 2.9
2.9 GPM Water Pressure System Pump
Features:

Smooth flow
Dry running capability
Soft noise absorbing mounts
Snap-fit port fittings
Built-in bypass - less pulsation
Reduces need for accumulator tank
Corrosion resistant materials
CSA listed
ISO 8846 MARINE (ignition protection)
CE
2.9 GPM Water Pressure System Pumps. Features:
Soft noise absorbing mounts. Snap-fit port fittings

[dbcape]

Do you have a hot water tank attached to the system? It could be that you are filling the hot water tank, (they can act as an accumulator), or perhaps the water tank has a drain that was left open? Check to see that all your other faucets are off, then check both hot and cold water flows from your faucet.

[Jannie Radiance]

[QUOTE=ranger42c;2412288]New pump? Maybe just some debris affecting the switch...

Or... is there sufficient supply from your freshwater tank?

When bleeding air, it's sometimes useful to open all the taps at once...

Otherwise, hidden leak, somewhere you can't easily see?

Our PAR MAX isn't a continuous duty pump, so it's intended to be used with an accumulator. Even with that, flow rate surges and ebbs a little. We haven't found that to be a problem...

-Chris[/Accumulator bro!]

[thinwater]

Originally Posted by Ivansgarage

It says NO accumulator....

Actually, what the Jabsco site says is...

"* Reduces need for accumulator tank"
31395 Series PAR-Max 2.9 > Switched Pumps > Xylem Flow Control - Let's Solve Water.

This is the probably the suggestion of the sales department. They push dumb claims like that. The engineers will tell you it really needs an accumulator tank.

In many installation the pipe will provide enough flexibility to prevent excess cycling. But with wear or a rigid system, it will cycle. Good engineering practice, in the interest of reliable operation, says you need an accumulator. Basic physics, no exceptions.

[44'cruisingcat]

Originally Posted by HopCar

When a pump like that won't shut off and there are no obvious leaks, I look at the valves inside the pump. They do wear out with age or something can get in and hold them open. It never builds enough pressure to activate the switch.

Of course the switch could be bad.

Had both of these happen.

[44'cruisingcat]

Originally Posted by Stu Jackson

Shurflo or Johnson.

Johnson were pretty bad for a while. The only leaky pump I ever had was a Johnson. Only a couple of years old.

[ThresherMan]

On a cautionary side note, I had to replace my fresh water pump due to the PO installing it upside down, i.e. the diaphram was above the motor housing, and leakage in the diaphram rusted the rotor.

[elandra65]

Very much sounds like air in the line from the tank to the pump which is compressible and fools the cutoff switch. Usually these pumps work very well and the flow should be constant with no spitting of air etc. However I have had a few problems with air in the system with mine and actually replaced one pump because I was convinced it was faulty. The new pump gives the same problem, spitting air and not switching off quickly so I still have a problem with the feed line. I am using whale quick connect fittings and I believe these work great under pressure but under a vacuum I suspect they are letting in air. Funny thing is it is an intermittent problem. BTW I am sure the instructions say not to use an accumulator with this pump.

regards

Andrew